horses can enter walls?

Put the summary of the bug you're having here

What I expected to happen was...:
i spawned some horses and just walked through, of course i expected nothing special to happen

What actually happened was...:
when i pushed a (baby) horse it just simply got into walls, the walls seem to just let the horses enter. after that they die of course. because they got stuck in the walls... i don't know if they can get THROUGH walls.

i really hope you can fix it.
greetings Anina